A few more bits of info from someone messaging me from the main site:
The Supermicro system runs 7-10 degrees C cooler with the cover removed from the chassis. Supermicro could have mitigated this matter by either placing a fan near the cpu or having vent hole perforations in the chassis cover over the motherboard.
The temperature in the closet in which my server resides typically runs ca. 64-76 deg F (depending on the time of day or night), well below the 95 deg F Supermicro recommends (I am, however, concerned that in the summer it may get much hotter in there). With the server’s chassis cover on, IPMI indicates the system temperature at 52 deg C and the CPU temperature at 60 deg C. With the cover off, the temperatures drop down to 47 deg C and 52 deg C respectively. These temperatures occur while one of my sons is playing an online game, so they are not idle temperatures—idle temperatures, however, do not appear to be much lower, typically 46 deg C and 49 deg C, respectively, at night when the room temp is ca 64 deg F.